Instar
441510
222878185
2008-07-01T15:33:42Z
Justinfr
3462111
Reverted edits by [[Special:Contributions/218.208.237.142|218.208.237.142]] to last version by Pro bug catcher (using [[WP:HG|Huggle]])
[[Image:eposlarvae.jpg|thumb|250px|''[[Epiphyas postvittana]]'' 5<sup>th</sup> instar larva]]
An '''instar''' is a developmental stage of [[arthropods]], such as [[insects]], between each [[ecdysis|moult]] (''ecdysis''), until sexual maturity is reached. Arthropods must shed the [[exoskeleton]] in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions or changes in the number of body segments. Some arthropods can continue to molt after sexual maturity, but these subsequent molts are generally not called instars.
For most insect species the term "instar" is used to denote the developmental stage of the [[larva]]l or [[Nymph (biology)|nymph]]al forms of [[holometabolous]] (complete metamorphism) or [[hemimetabolous]] (incomplete metamorphism) insects, but the term can be used to describe any developmental stage including [[pupa]] or [[imago]] (the adult, which does not molt in insects).
[[Image:PICT1516.JPG|thumb|300px|Two instars of a caterpillar of ''[[Papilio polytes]]'']]
The number of instars an insect completes depends on the species and the environmental conditions. Cooler temperatures and lower humidity often slow the rate of development.
[[Category:Developmental biology]]
[[Category:Entomology]]
[[Category:Arthropods]]
{{arthropod-stub}}
[[pt:Ínstar]]
[[sk:Instar]]